When someone shows interest in you for a short period of time then becomes a cockmunch and completely ignores your existence once they are bored of you. Happens most commonly after you've been told "I love you" or your virginity has been taken.
"Hey, so Alex hasn't been texting me like he always does, you think hes sick or something?"
"Sorry, I think he has Antonio Syndrome. But it's okay. This is the world's way of saying 'He's not worth your time.'"